The present invention generally relates to farm machinery and harvesting equipment. More particularly, the invention relates to apparatus and methods for ridding harvested crops of foreign matter such as weed seeds, insects, etc.
A combine is a vehicle used to harvest crops by cutting off plant tops and then threshing the crops by beating and separating the grains from the plants while the vehicle continues to move across a field. At a front end, blades are employed to cut down plants. The cut plants are then directed into a sieve section where they are subjected to beating and sieving to release the grain and air is blown through the sieve section to separate light foreign matter from the grain. The light foreign matter is then carried away entrained in the air. The grain is collected and then directed into a storage hopper or into an accompanying storage vehicle such as a trailer. An example of such a combine is that manufactured by International Harvester and sold under the designation Model 815.
Usually, the grain produced by the threshing process still includes weed seeds that are too heavy to be entrained in the air. Thus, the grain still includes what is referred to herein as foreign matter.
In addition to the foregoing, the matter removed from the harvested crop during threshing is returned to the ground by simply allowing the matter to be blown out the back or off to a side of the combine. Because the matter can contain a variety of seeds, these seeds can germinate and produce undesirable weeds during a subsequent planting.
Current methods for preventing such germination involve spraying chemicals. However, these chemicals can present a hazard in the food chain, as well as to the environment.